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Java API for modeling web page content and relationships in a Servlet environment.

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/*
 * semanticcms-core-servlet - Java API for modeling web page content and relationships in a Servlet environment.
 * Copyright (C) 2016, 2017, 2018, 2019, 2020, 2021, 2022  AO Industries, Inc.
 *     [email protected]
 *     7262 Bull Pen Cir
 *     Mobile, AL 36695
 *
 * This file is part of semanticcms-core-servlet.
 *
 * semanticcms-core-servlet is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * semanticcms-core-servlet is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with semanticcms-core-servlet.  If not, see .
 */

package com.semanticcms.core.servlet;

import com.aoapps.collections.AoCollections;
import com.semanticcms.core.model.Page;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletException;

/**
 * A page cache that is not thread safe and should only be used within the
 * context of a single thread.
 */
class SingleThreadCache extends MapCache {

  private final Thread assertingThread;

  @SuppressWarnings("AssertWithSideEffects")
  SingleThreadCache() {
    super(
        new HashMap<>(),
        VERIFY_CACHE_PARENT_CHILD_RELATIONSHIPS ? new HashMap<>() : null,
        VERIFY_CACHE_PARENT_CHILD_RELATIONSHIPS ? new HashMap<>() : null,
        new HashMap<>()
    );
    Thread t = null;
    // Intentional side-effect from assert
    assert (t = Thread.currentThread()) != null;
    assertingThread = t;
  }

  @Override
  Page get(CaptureKey key) {
    assert assertingThread == Thread.currentThread();
    return super.get(key);
  }

  @Override
  void put(CaptureKey key, Page page) throws ServletException {
    assert assertingThread == Thread.currentThread();
    super.put(key, page);
  }

  @Override
  public  Map newMap() {
    assert assertingThread == Thread.currentThread();
    return new HashMap<>();
  }

  @Override
  public  Map newMap(int size) {
    assert assertingThread == Thread.currentThread();
    return AoCollections.newHashMap(size);
  }

  @Override
  public void setAttribute(String key, Object value) {
    assert assertingThread == Thread.currentThread();
    super.setAttribute(key, value);
  }

  @Override
  public Object getAttribute(String key) {
    assert assertingThread == Thread.currentThread();
    return super.getAttribute(key);
  }

  /**
   * {@inheritDoc}
   *
   * @param    An arbitrary exception type that may be thrown
   */
  @Override
  // TODO: Ex extends Throwable
  public  V getAttribute(String key, Class clazz, Callable callable) throws Ex {
    assert assertingThread == Thread.currentThread();
    return super.getAttribute(key, clazz, callable);
  }

  @Override
  public void removeAttribute(String key) {
    assert assertingThread == Thread.currentThread();
    super.removeAttribute(key);
  }
}